For three of my cats I by food in the 18-20# bags. It last about 6 weeks or so.
For Ox I buy a much smaller bag 5# maybe??? I keep his in the house but the others is emptied into a hanging bin on the wall of the garage.
I know people food can get stale but what about pet food????

I buy the 18# bag of nutro natural for three of the cats that is stored in a big that empties into a container when the handle is pulled-they don't have the probelm. Ox's food Chicken Soup for Cat Lovers soul its the 7-9# bag. But I think he wasn't eating due to losing a tooth (fang) he seems ok now.